• 대한기계학회논문집B
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• 제27권4호
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• pp.476-483
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• 2003

A mathematical model is presented to predict the two-phase flow and heat transfer phenomena of the evaporating extended meniscus region in a micro-channel. The pressure difference at the liquid-vapor interface can be obtained by the augmented Laplace-Young equation. The correlative equations for film thickness, pressure, and velocity in the meniscus region are derived by applying the mass, momentum, and energy equations into the control volume. The results show that increasing the heat flux and the liquid inlet velocity cause the length and liquid film thickness of the extended meniscus region to decrease. The variation, however, of the heat flux and liquid inlet velocity has no effect on the profile of film thickness. The majority of heat is transferred through the thin film region that is a very small region in the extended meniscus region. It is also found that the vapor velocity increases gradually in the meniscus region. However, it increases sharply at the junction of the meniscus and thin film regions.

• 한국정밀공학회지
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• 제29권4호
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• pp.455-460
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• 2012

The Electrostatic Inkjet system has many applications in cost and time effective manufacturing of printed electronics like RFIDs, OLEDs and flexible displays etc. This paper presents pneumatic ink supply system for an electrohydrodynamic deposition (EHD) setup for the precise pressure control to produce a small amount of discharge at the end of the capillary. The meniscus shape depends upon the applied pneumatic pressure to the ink supply system. Furthermore, this paper also compares meniscus shapes at different applied pneumatic pressures. It is concluded that patterning of constant line-width can be achieved better by controlling the meniscus shape using this technique.

• 대한관절경학회지
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• 제3권1호
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• pp.54-61
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• 1999

광범위한 반월상 연골 손상에 대한 최근의 치료는 수많은 연구와 임상적 접근을 통해 정상적인 반월상 연골의 기능을 회복하기에 이르렀다. 냉동 보관된 반월상 연골의 동종이식은 연골의 정상적인 회복을 위한 유용한 방법중 하나이다. 저자들의 첫 4례의 동종연골이식은 관절경의 도움으로 시행하였고, 이후 22 예에서는 최소한의 관절 절개를 이용하였다. 또한 모든 동종 연골 이식에서 반월상 연골의 안정성과 회복을 위해 반월상 연골에 골교를 부착하여 고정하였다. 전방 십자 인대 재건술은 반월상 연골 동종이식술시 동시에 시행하였다. 내측 반월상 연골은 일명 Key-hole technique을 사용하여 골터널에 의한 관절 연골의 침습을 최소화하려 하였다. 우선 반월상 연골의 골교를 원통형으로 만들고 수혜자의 슬관절의 전방 십자 인대의 내측연을 따라 골 터널을 만들어 반월상 연골의 골교를 press-fit하도록 한다. 삽입된 반월상 연골은 일반적인 반월상 연골 봉합술로 관절경을 이용하여 봉합한다. 외측 반월상 연골은 내측 반월상 연골과는 달리 반월상 연골의 골교를 반원통 모앙으로 만들고 수혜자의 슬관절의 전방 십자 인대의 외측연을 따라 반원통 모양의 골 요지를 만든다. 반월상 연골을 골 요지에 얻고 인도 봉합사를 경골의 전면으로 뽑아내 이를 묶음으로써 고정을 한다. 삽입된 반월상 연골은 내측 반월상 연골이식술과 같은 방법으로 봉합한다. 저자들은 이와 같은 방법으로 관절 연골의 침습을 최소화하고 비교적 정확한 위치에 반월상 연골을 이식할 수 있었다.

• 대한치과교정학회지
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• 제21권1호
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• pp.53-76
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• 1991

The study was designed to analyse the reorganization of the rabbit TMJ meniscus which was anteriorly displaced by surgery. The author compared the anteriorly displaced groups with control group. After surgical opening of the left rabbit TMJ space, cut the posterior attachment of the meniscus, and pushed it under the undercut area of the condyle head. Experimental groups were sacrificed by 1, 2, 4, 8 weeks after surgery. The samples were analysed with light microscope under T-B stain and electron microscope. The results were as follows: 1) The rabbit TMJ meniscus consisted of thick anterior and posterior band running different way, and comparative thin intermediate band runining antero-posteriorly. 2) Round oval shape chondrocyte-like cells were imbeded between the collagen fiber bundles and composed of proteoglycan granules, that showed metachromasia with toluidine blue, around the cell matrix. 3) Type II collagen fiber bundles in experimental group occured degenerative changes in organic patterns at 8 weeks, but those of type I collagen fiber bundles sustained longer, 4) The typical fibrocartilage of the rabbit TMJ meniscus was changed into fibrotic mode in process of time and showed the degenerative changes, which contained hyperplasia, calcification, resorption and hyalinization in the connective tissue. 5) The hyperplastic change of the synovial membrane in 4 week group and transitional change from fibrocyte to chondrocyte in cell type in 8 week group were observed. 6) The diameters of collagen fibers were diminished with the degenerative changes, the shape of the fibers became wavier and more nonorganic in running pattern and fiber bundle spaces widened.

• 대한정형외과스포츠의학회지
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• 제5권2호
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• pp.155-160
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• 2006

목적: 경골과 골절과 동반된 외측 반월상 연골 손상에서 봉합술 및 부분 절제술 후 치료 결과를 분석 하고자 하였다. 대상 및 방법: 1953년 2월부터 2004년 8월까지 경골과 골절로 치료 한 23명, 24예의 외측 반월상 연골 파열을 대상으로 하였다. 파열의 형태는 반월상 연골-관절낭 경계부의 종 파열 (14예, 66.7%)이 가장 많았다. 모든 골절은 관절경과 영상 증폭기의 감시하에 정복을 하였으며 반월상 연골 종 파열은 관절경하 수직 봉합술을, 나머지는 부분 절제술로 치료 하였다. 임상적 결과를 Ikeuchi의 평가 기준에 따라 분류하고 수술 전과 후의 Lysholm 점수를 비교 하였다(paired t-test). 결과: Ikeuchi 평가 기준에 따른 결과는 봉합술을 시행한 14예중 우수 12예 (85.7%), 양호 12예 (7.1%), 보통1예 (7.1%)였으며, 부분 절제술을 시행한 6예 중 우수는 4예 (66.7%), 양호는 2예(33.3%)를 보였다. Lysholm 점수는 수술 전 평균 56.6점에서 수술 후 92.3점으로 증가 하였다(p<0.0001, paired t-test). 결론: 경골과 골절은 외측 반월상 연골의 봉합술이나 부분 제거술의 결과에 나쁜 영향을 끼치지 않는 것으로 사료된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.612-615
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• 1996

In the continuous casting process, molten metal contacts the mold wall and the molten metal surface is subject to the mold oscillation. The mold oscillation results in the oscillation marks on the surface of solidified steel, which has undesirable effects on the quality of slabs. In order to reduce the oscillation marks by achieving soft contact of molten metal with the mold surface, alternating magnetic field is applied to the surface of molten metal. However, if the magnetic field strength becomes too strong, the melt flow induced by the magnetic field. causes the instability of the molten metal surface, which has also the bad influence on the slab quality. Therefore, it is very important to choose the optimal position of the inductor coil and the optimal level of electric power to minimize the surface defects. In the present work, as a first step toward the optimization problem of the process, numerical studies are performed to investigate the effects of coil position and the electric power level on the meniscus shape and the flow field. As numerical tools, the boundary integral equation method(BIEM) is used for the magnetic field analysis and the finite difference method (FDM) with orthogonal grid generation is used for the flow analysis.

• 전기학회논문지
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• 제56권8호
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• pp.1441-1444
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• 2007

This paper presents a novel electrostatic drop-an-demand ejector with a conductive pole inside nozzle. The MEMS fabricated pole-type nozzle shows a significant improvement in the performance and reliability of forming meniscus and generating a micro dripping mode of droplet out of the meniscus. It is verified experimentally that the use of the pole-type nozzle. The liquid is used D20+SDS+SWNT (5 %wt). The gap between upper electrode and nozzle is about 600 um. Electrostatic drop-an-demand ejection is observed when a DC voltage of 1.5 kV is applied between the control electrode and ground electrode. Droplet diameter is $100{\mu}m$.

• 청정기술
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• 제20권2호
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• pp.97-102
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• 2014

현재 고효율 백색 발광다이오드(light emitting diode, LED) 구현을 위한 고점도 형광체 토출에 대한 많은 연구가 진행 중이다. 백색 발광다이오드에서 제품성능에 영향을 미칠 수 있어 고점도 형광체의 정량토출은 중요하다. 그러나 기존 연구에서 고점도 형광체 정량토출의 어려움이 있었다. 고점도 형광체의 정량토출을 위해서 본 연구에서는 다양한 점도에서 미세토출이 가능한 정전기력 프린팅 기술을 적용하였다. 전압 변화에 따른 요구 적출형(drop on demand, DOD) 토출 실험을 진행하여 토출 시 노즐의 메니스커스 각도와 토출 도트 직경 사이의 상관관계를 도출하였다. 토출 전압이 증가함에 따라, 토출 메니스커스 각도는 증가하고 토출 도트 직경은 감소하였다.

• 한국주조공학회지
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• 제23권5호
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• pp.257-267
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• 2003

In early solidification during the continuous casting of steel slabs, the formation of oscillation marks on the surface of slabs was mainly affected by carbon contents and casting conditions. The control of oscillation mark is required for the HCR(Hot Charged Rolling) process because the deep oscillation marks seriously deteriorate the surface qualities of steel slabs. The metallographic study has revealed that the oscillation mark can be classified principally according to the presence or absence of a small 'subsurface hook' and the depth of the oscillation marks in the subsurface structure at the basis of individual oscillation marks. The subsurface hook of oscillation marks was either straight or curved. When the amount of overflow was small and the subsurface hook was formed in the top of oscillation marks, the subsurface hook was straight and the oscillation mark was shallow. The oscillation marks without subsurface hook have small early solidification shell and were formed wide. The actual negative strip time$(t_N)$ was changed by the effect of meniscus level fluctuation Therefore irregular early solidification shell and oscillation mark were formed.

• 대한본초학회지
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• 제32권2호
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• pp.41-47
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• 2017

Objective : The aim of this study is to investigate anti-arthritis activity using a korea's natural monument No. 265 designate 'Yeonsan-Ogye'. In this study, research by using extracts from different concentration of the Yeonsan-Ogye through an MIA-induced arthritis animal model was being conducted in vivo and scientifically verifying the efficacy of medicinal food. Methods : Yeonsan-Ogye was administered 500 mg/kg/day, 1000 mg/kg/day, 2000 mg/kg/day to SD-Rat, where arthritis was induced by monosodium iodoacetate (MIA) at $60mg/m{\ell}$. MMP-9, COMP, CTXII, calcitonin and glycosaminoglycan level in serum were measured by ELISA. The changes of relative hind paw weight bearing ratio by Incapacitance Test Meter and The cartilage of meniscus volume was examined and 3-D high-resolution reconstructions of the cartilage of meniscus were obtained using a Micro-CT system. Also, the histopathological analysis of knee was observed by H&E and safranin-O staining. Results : Production of MMP-9, COMP (all groups) and CTXII (500, 1000 mg/kg/day) level in serum was decreased, respectively, in comparison with control. The other way, production of calcitonin (500, 1000 mg/kg/day) and glycosaminoglycan (all groups) level in serum, Hind paw weight bearing ratio (all groups) was increased, espectively, in comparison with control. The cartilage of patella volume in micro-CT increased significantly. In addition, all groups showed a increase in the cartilage volume and proteoglycan. Conclusion : The results for Yeonsan-Ogye showed significant antiarthritis activity in serum and the cartilage. Therefore, it is thought to be that Yeonsan Ogye can be utilized as a variety of new korea medicie and health foods against arthritis diseases.